Question

我有一个表bean：

public class Employee implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    @Column(name = "employee_id", unique = true, nullable = false)
    @Basic(fetch = FetchType.EAGER)
    private long id;
}

当我尝试在数据库中插入行时，出现“无法将数据库状态与会话同步”：

19658 [http-bio-8080-exec-2] WARN org.hibernate.util.JDBCExceptionReporter - SQL Error: 0, SQLState: null
119658 [http-bio-8080-exec-2] ERROR org.hibernate.util.JDBCExceptionReporter - Batch entry 0 insert into employee (basic_salary, code, fk_department_id, email, first_name, ip_phone_extension, is_default, last_name, password, threshold, voice_model, voice_validate, employee_id) values (NULL, 222, NULL, admi222222222n@xeno-solutions.com, sdfasfd, 21312, 0, fdsafsad, 2, NULL, NULL, NULL, 10) was aborted.  Call getNextException to see the cause.
119658 [http-bio-8080-exec-2] WARN org.hibernate.util.JDBCExceptionReporter - SQL Error: 0, SQLState: 23505
119658 [http-bio-8080-exec-2] ERROR org.hibernate.util.JDBCExceptionReporter - ERROR: duplicate key value violates unique constraint "employee_pkey"
  Detail: Key (employee_id)=(10) already exists.
119658 [http-bio-8080-exec-2] ERROR org.hibernate.event.def.AbstractFlushingEventListener - Could not synchronize database state with session
org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:96)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:179)
    at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51)
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1206)
    at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:375)
    at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:137)
    at org.springframework.orm.hibernate3.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:656)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:754)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:723)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:393)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:120)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
    at $Proxy35.addEmployee(Unknown Source)
    at com.xeno.phoneSuite.beans.EmployeeBean.addOrUpdateEmployee(EmployeeBean.java:256)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.el.parser.AstValue.invoke(AstValue.java:262)
    at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:278)

为什么出现此异常以及如何解决它？注意：我使用sql脚本将数据添加到数据库

Answer 1

日志写道：

119658 [http-bio-8080-exec-2]错误org.hibernate.util.JDBCExceptionReporter - 错误：重复键值违反了唯一约束＆＃34; employee_pkey＆＃34; 细节：Key（employee_id）=（10）已经存在。

ID必须是唯一的，但您尝试使用数据库中已存在的ID创建新的Employee。 id生成器的工作是确保这样的事情不会发生。

hibernate文档writes：

SEQUENCE（在Hibernate中称为seqhilo）：在给定命名数据库序列的情况下，使用hi / lo算法有效地生成long，short或int类型的标识符。

该生成器失败的最常见原因是它的序列与实体表不同步，例如因为实体是在没有经过休眠的情况下创建的（例如通过SQL脚本），并且序列未更新。 / p>

Answer 2

我认为这一行：

Detail: Key (employee_id)=(10) already exists

放弃它。检查数据库中的内容：

select * from employee where employee_id=10

Answer 3

我通过GenerationType.IDENTITY

解决了这个问题

public class Employee implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "employee_id", unique = true, nullable = false)
    @Basic(fetch = FetchType.EAGER)
    private long id;
}

将为每个表序列和sql脚本生成我们不在insert语句中添加id

无法在hibernate中将数据库状态与会话异常同步

3 个答案: